The first season explored the gangland wars of Melbourne from 1995 to 2006. After Victorian Police finally intercepted two contract killings in 2004, leading to multiple arrests, the death toll stood at 33, making it one of the bloodiest crime wars in the western world. Based on the book "Leadbelly" by John Silvester and Andrew Rule

The second season, "A Tale of Two Cities", follows the Australian criminal landscape that changed forever in the mid 1970s when the illegal drug industry took hold. In the decade between 1976 and 1986 the marijuana and heroin business expanded exponentially. Crooks with enough nerve, brains and imagination stood to make millions. Two of the biggest crooks of all were "Aussie Bob" Trimbole and Terry "Mr Asia" Clark. This is their story. This is also the story of the nascent Federal Police, their efforts to understand the nature and extent of organised crime in Australia, and their fight against the pernicious heroin trade.

The third season, "The Golden Mile", is based on real events that stemmed from the nightclub scene of the Sydney suburb of Kings Cross. The timeline of the series is the years between 1988 and 1999 and primarily depicts the running of Kings Cross and the corruption of police leading up to the 1995 Wood Royal Commission.

The fourth season, "Razor", detailed the 'razor gangs' who controlled the city's underworld during the era of the late 1920's and early 1930's and the violent battle between the two "vice queen" powers, Kate Leigh and Tilly Devine. Embroiled in both of these wars were notorious prostitute of the era, Nellie Cameron, and Australia's still-young police force, trying to find its feet amidst the violence.